The biosynthesis of retinal cell membranes will be explored using new techniques of immunochemical subcellular fractionation. This approach will use recently prepared antibodies against proteins of the rod outer segment (ROS). Specificity of these antisera has been demonstrated by a new technique of immunoelectrophoresis. With this technique and successful approaches of subcellular fractionation we have demonstrated that a rhodopsin precursor is membrane-bound prior to its assembly in the ROS. We wish to develop new procedures for isolation of antibodies against peptides isolated from rhodopsin. Antibodies will be used to immunoprecipitate membranes bearing the rhodopsin precursor after brief incorporation periods of labeled amino acids. Concurrent transport of other ROS proteins will be examined with antibodies to a large ROS protein (molecular weight approximately 300,000 daltons). These antibodies do not cross react with rhodopsin. The technology developed in these studies will be applied to the analysis of two new forms of retinal dystrophy. We have described an inherited retinal dystrophy in a Wag/Rij rat colony at Yale. The dystrophy differs considerably from the RCS rat retinal dystrophy. Photoreceptor degeneration appears to be the primary lesion rather than disorders of rhodopsin phagocytosis by pigment epithelium. The end stage lesion resembles human retinitis pigmentosa. A possibly analogous dystrophy has been described in sheep ingesting large amounts of a retinotoxic fern, bracken (Pteridium aquilinum). Histopathologic analysis of the retinas of experimental animals fed bracken will be initiated in order to delineate the pathogenesis of the lesion. Application of the techniques of membrane biosynthesis will be applied to these dystrophies as appropriate. Limited analysis of membrane biosynthesis in human retinoblastoma will be considered with the use of convalescent sera from children bearing these tumors which have antimembrane antibodies.